What is a Tax Assessment?
A tax assessment is the process by which a local government appraisal district determines the value of a property for the purpose of calculating property taxes. The assessment establishes the property's assessed value, which is multiplied by the local tax rate to determine the annual tax bill. Tax assessments are conducted annually in most jurisdictions, though the specific process, timing, and methodology vary by state and county.
The tax assessment is not an appraisal in the traditional sense. Licensed appraisers inspect individual properties and provide detailed valuations. Tax assessors use mass appraisal techniques to value hundreds of thousands of properties simultaneously, which means their assessments are necessarily less precise. This creates both challenges and opportunities for property owners and investors.
The annual assessment cycle in Texas
In Texas, the county appraisal district values all properties as of January 1 each year. The district sends notices of appraised value in April or May, giving property owners approximately 30 days to file a protest if they disagree with the valuation. The Appraisal Review Board (ARB) hears protests from May through July. Tax rates are set by each taxing entity (county, city, school district) in August through October. Tax bills are mailed in October and due by January 31 of the following year.
This timeline matters for investors. If you purchase a property mid-year, you need to know both the current year's assessed value (which determines the current tax bill) and whether the assessed value is likely to change after the purchase. A significant purchase price above the current assessed value may trigger a reassessment in the next tax year, increasing future taxes.
What the assessor looks at
The appraisal district maintains records for every property in the county, including physical characteristics (square footage, bedrooms, bathrooms, year built, lot size), improvements and additions, land classification and zoning, recent sale prices (for the subject property and comparables), and any special features that affect value. Most of this data comes from building permits, deed recordings, and aerial/street-level photography. Interior inspections are rare unless the owner requests one during a protest.
The district uses computer-assisted mass appraisal (CAMA) models to estimate values. These models apply adjustments based on location, property type, size, age, and recent sales in the area. Because the models apply averages, they can miss property-specific issues like foundation problems, flood damage, outdated systems, or recent renovations that significantly affect the true value.
Protesting your tax assessment
Property tax protests are one of the most underutilized tools in real estate investing. In Texas, approximately 50% of protests result in a reduction, with average savings of $500-$2,000 per year. For investors with multiple properties, the cumulative savings can be substantial. The protest process is free (you can do it yourself) or relatively inexpensive ($200-$500 if you hire a property tax consultant).
Effective protest evidence includes recent comparable sales at prices below your assessed value, photos documenting property condition issues (deferred maintenance, foundation cracks, roof damage), evidence of incorrect property characteristics in the district's records, and any factor that would make your property less desirable than the district's model assumes. An independent appraisal is the strongest evidence but is usually only cost-effective for higher-value properties.
Assessment changes after purchase
When a property changes hands, the appraisal district takes notice. The sale price becomes a data point in their records and may influence the next assessment. If you purchase a property for significantly more than its current assessed value, expect the assessment to increase toward the purchase price in the next tax year. Conversely, if you acquire a distressed property at below the assessed value, you have strong evidence for a protest.
For fix-and-flip investors, renovations that are captured through building permits may trigger a reassessment. A $50,000 renovation on a $150,000 assessed property could result in a reassessment to $200,000+. While this increases the property's value (which is good for your sale price), it also increases the tax burden for the next owner, which savvy buyers factor into their offers.